Batsugun

Much in the same way that Twin Cobra was the template for Raiden-style shmups or Truxton for boring tanky wave-based Euro slop, Batsugun, especially the Special version, took the reduced hitbox of Grind Stormer, made it even smaller, and dramatically increased both the power of the player's weapons and the number of bullets fired by enemies.

Input lag is effectively nil; using a basic generic X360 gamepad I can't feel any delay between my inputs and the response on screen.

Fun weapons and good difficulty curve (at least through the first 3 levels, I'm playing on one credit so I've yet to reach stage 4.) Quite detailed and beautiful pixel art that holds up wonderfully as well.

I have played the game through Retroarch for a long time too and this has been my go to as the input lag is very low and the graphics/sound being very well emulated.

Complementing the action is an energetic soundtrack that perfectly matches the frantic pace, helping maintain excitement from the opening stage to the final confrontation.